1. The Field of the Invention
A self-locking cable connector useful in wireline data telemetry operations or in wireline logging of boreholes is the principal focus of this invention. Although the invention preferably relates to connections for braided cable, the connector of this invention may also be used for coaxial cables or other wiring. The preferred connector of this invention is durable so that it will withstand the hostile environment of drilling fluid circulation in a rotary drilling operation.
2. A Description of the Prior Art
When wireline data telemetry operations are conducted during rotary drilling, a wireline or cable is normally extended in the drill string from a location near the drill bit to the surface. Connectors are used to connect various segments of the cable in the drill string. The corrosive power of the drilling fluids used during rotary drilling presents a problem in maintaining the integrity of these connections. The drilling fluids effect the durability of the connectors and, in some cases, seeps into the connectors to cause a loss of electrical signal. Available connectors have the disadvantage that they are too large and too inflexible either to easily pass through the sheave equipment used to pay cable in or out or to spool with the cable for storage. Also, the threaded connections of available connectors have threaded connections which sometimes unwind during the drilling operations causing a loss of electrical signal.
In the elecrical component art, Kornick (U.S. Pat. No. 3,681,739) discloses a sealed coaxial cable connector which seals the spaces of the connector that surround the connector heads. The connector preferably has a plug and a receptacle which are connected in a bayonet-type connector arrangement. Pins follow L-shaped slots, and are held under spring bias to maintain electrical contact. Concelman (U.S. Pat. No. 3,694,793) discloses a quick connect coaxial coupling using a split outer shell, latch-type coupling that releases when two tabs are pressed inwardly. Locke et al. (U.K. Pat. No. 1,289,390) discloses a plug and socket connector having a spring-loaded sleeve with a means for securing the plug. The securing means is designed to allow the plug and socket to separate upon application of a predetermined axial load.
Until recently, inventors have not focused on the complex problems associated with the use of electrical connectors in wellbore data telemetry. The connectors for data telemetry preferably are preferably simple in construction, simple in operation, durable, and reliable. These factors will facilitate their use and acceptance in the field, where system failure translates into sizeable expenses. Because wirelines must often be cut to length for each use, the connectors are preferably capable of being quickly and easily assembled and disassembled at the field site. The complete connector preferably will provide a dependable connection, especially when submersed in the hostile environment of circulating drilling mud (i.e. the connector will stay together and the connection will remain intact). The connector will preferably maintain the connection throughout all drilling operations. Furthermore, the connector preferably will be designed so that the cable it connects can be tensioned. Improvements in available connectors to provide a suitable connector for wireline data telemetry operations are still being sought by the industry.